This unnamed Scout Leader was a victim of Fiona Duncan.
This man brought a group of children on a tour to a museum which featured a New World shipwreck, belonging to The Star. By evening, the man was urging the students to get into Mr. Peterson's van and then he excused himself for a minute.
The man ran back into the building to use the restroom. As he attempted to wash his hands, the lights began flickering, the doors of the toilet stalls began opening and closing, and the room began to cool down rapidly, enough that he could see his own breath.
He looked down and noticed the water from the tap turning into ice. When he looked back up, he saw a hooded figure in the broken reflection. The man turned round, covered his face and screamed, unable to do anything else as the hooded figure charged towards him and murdered him.
Sam and Dean Winchester arrived at the museum sometime after, having suspected a ghost attack after another teacher had been murdered earlier. They soon discovered that The Star belonged to Gavin MacLeod, its former captain before he time traveled to the present. With Gavin's help, they later found out that the killer was Fiona Duncan, a crewman on board the ship who was out trying to get revenge on her own teacher for betraying her, by killing every other teacher she could find, such as the Scout Leader.
To prevent the killings, Gavin was sent back in time to keep Fiona safe. This ensured that their teacher, Mistress Aloway, could not cause her harm or even encourage it. With the timeline fixed, the Scout Leader and all of Fiona's other victims were brought back to life, as if the killings never happened.